Update adastamedia.md (#1501)
Update adastamedia.md (#1501)

Adasta Media is an aliased bidder for AppNexus.
Adasta Media no longer relies on Gamoshi for publication in Prebid. This new one replaces the existing one in your listings.
prebid/prebid.github.io,sonobi/prebid.github.io,sonobi/prebid.github.io,prebid/prebid.github.io,sonobi/prebid.github.io,prebid/prebid.github.io